THE HAGUE, July 31 -- Purse-lipped and gaunt, Radovan Karadzic appeared before a U.N. war crimes tribunal for the first time Thursday and in sharply worded Serbian vowed to defend himself against genocide and other charges "as I would defend myself against any natural catastrophe."

In remarks that were cut short by the judge, the former Bosnian Serb leader suggested he would attempt to expose alleged double-dealing by the West, particularly the United States, in the wake of the 1992-1995 Bosnian war. That could presage the kind of political grandstanding that former Yugoslav president Slobodan Milosevic, who also represented himself, used to sidetrack his prosecution before he died in his cell at the tribunal's detention center.

Except for two guards who flanked him, Karadzic's side of the court was empty. "I have an invisible adviser, but I have decided to represent myself," said Karadzic, 63, who was dressed in a dark blue suit and tie and carried a black briefcase.

Shorn of the beard and long hair that helped disguise him as an alternative-health guru in Belgrade, Serbia's capital, Karadzic listened mostly impassively as Judge Alphons Orie read a summary of the indictment. Karadzic's trademark shock of hair, swept back from his forehead, was restored by a haircut before his extradition from Serbia, but he has visibly aged since going on the run in 1997.

The former president of the Bosnian Serb republic and supreme commander of Bosnian Serb forces faces two counts of genocide arising from the siege of Sarajevo and the 1995 massacre of 8,000 Muslim men and boys in the town of Srebrenica, the single worst atrocity in Europe since the end of World War II. Karadzic also faces other charges, including crimes against humanity and murder, for "ethnic cleansing" and creating prison camps where Bosnian Muslims and Bosnian Croats were killed, sexually assaulted and brutalized.

Karadzic's military commander on the ground, Ratko Mladic, who is also wanted on genocide charges, remains at large.

Karadzic declined to enter a plea during the 70-minute hearing, exercising his right not to do so for 30 days. He answered a series of simple questions, sometimes with a flash of humor. Asked, for instance, if his family knew where he was, Karadzic said, "I do not believe there is anyone who doesn't know that I am in detention." When the judge inquired as to conditions since he arrived in the Netherlands, Karadzic said he had been "in worse places."

Karadzic was prevented from reading in full a four-page statement he had prepared, although he managed to tell the court that he had wanted to appear before the tribunal soon after his 1995 indictment. He suggested a deal had been cut with U.S. diplomat Richard Holbrooke, who negotiated the Dayton peace agreement ending the war in Bosnia, that Karadzic would not be sent to The Hague if he didn't endanger the accord.

"My commitment was to withdraw . . . even from literary life and all sorts of public life," said Karadzic, a trained psychiatrist and a poet. In return, he said, "the United States of America would fulfill its commitments."

Holbrooke dismissed the allegation.

"It's an old story by one of the worst mass murderers in the world, and it's completely untrue," Holbrooke said in a phone interview. "There was no deal. It would have been immoral, illegal and disgraceful."

The judge told Karadzic that an initial court appearance was not the place to raise those allegations, adding that the court would consider what Karadzic has to say if and when he files a formal written submission.